Aside from the actual electromagnetic desired signals, which are used, for example, for measuring distances, interference signals also arise in radar sensors, such as HF-interference signals, in particular. These interference signals can have a negative effect on the quality of the measurement of the desired signals, by means of which measuring errors, or at least defective measurements, may occur. In order to reduce the effect of the interference signals, internal shielding measures are normally provided. These absorb the interference signals, or shield at least the measurement systems and/or the transmission means from the effects of the interference signal.
These include, for example, metallic shields, which primarily result in a reflection of the interference signals. In addition to the metallic shields, radar-absorbing materials are used, which receive the interference signals prior to or after a reflection, and preferably absorb said signals entirely.
Radar absorbing elements are known in the prior art, which are formed from special, filled elastomer foams and/or from plastic foams. These foams are available on the market in the form of solids, as self-adhesive mats, which can be cut to size, in accordance with the respective application, and can be placed in the radar sensors, or can be placed on the radar sensors.
The disadvantage with the solution in the prior art is, in particular, that the installation of the foam mats, cut to size, normally occurs manually thereby. The foam mats are also normally produced from standardized materials, whereby a specific adaptation of the absorbent properties and the height geometries on an individual basis is not possible, or is only possible with great difficulty. Furthermore, small conductive particles arise during the cutting of the foam mats to size, in particular at the edges of the cuts, which can detach from the elements cut to size, which can lead to risks in terms of quality, both during the production, as well as later, in the fully assembled radar sensor. Furthermore, an automated installation of the tailored element is not possible.
Rubber-like flat absorbers are also known, which display a narrower band effect at higher costs and display disadvantages with an automated processing of the cutting to size.